97年2月22日(五) 2:00 ~3:00 P.M.
演講者姓名: 王清雲 教授
演講者服務單位: Division of Public Health Sciences, Fred Hutchinson Cancer Research Center
Instrumental Variable Estimation in Logistic Regression With Covariate Measurement Error When Repeated Surrogates Are Not Available
Abstract
We consider logistic regression when covariates are measured with errors. When a gold standard measurement for an exposure variable is not available for any of the study subjects, a common approach is to use repeated surrogate variables. However, in some real examples, there is only one surrogate variable available for each subject. To deal with an identifiability issue, a general approach is to search for a variable that is relevant to the unobserved covariates. The variable, that can provide useful information about the unobserved covariate, is often considered as an instrumental variable. In this article, we investigate estimation for the logistic regression when there is a single unbiased surrogate and a single instrumental variable. In addition to the estimation of the regression parameters, an important issue is to estimate the standard error of the measurement error. The result can be applied to studies when repeated surrogates for an unobserved covariate are not available. Results from a simulation study are presented to show the finite sample performance of the method.
Keywords: conditional score, corrected score, error-in-variable, functional methods.